A team of palaeontologists recently announced remarkable results from one of the largest tranches of pre-human fossils ever found in anthropological history. These two-million-year-old bones likely belonged to five individuals of a genus called Australopithecus sediba (A. sediba), among the many supposed intermediaries between apes and humans. The palaeontologists say that in spite of the fossil’s several ape-like attributes, the arch of its feet, its wrists and pelvis size are strikingly similar to ours and thus make it the best candidate yet for being our ancestor.
While the last decade— thanks to several novel fossil finds—is considered among the most productive in terms of such finds, it has, instead of clarifying, further muddied our understanding of our evolutionary history. So, for instance, while it is well accepted that bigger brains were a defining attribute of the path from apes to humans, A. sediba, with a brain smaller than that of its ancestors, is a glaring mismatch. Also, for birthing babies with bigger brains, pelvises are supposed to have flared up over time, but again A. sediba’s smaller pelvis is an incongruity. Indeed, this species could very well be a so-called evolutionary “dead-end”, but then what explains those amazingly human limbs that were more modern than several of its descendants?
Biologists and archaeologists have always maintained that the biggest hurdle to clearing these muddles is the paucity of fossils bearing traces of man’s descent from the apes. Now that more fossils are being discovered, how willingly can we concede that we could have been barking up the wrong tree in defining what it means to be human? Larger brain sizes and pelvises maybe among the more palatable non sequiturs of our evolutionary descent, but if in the future, more fossils and a better understanding of genetics were to reveal that abstract reasoning, spoken language and empathy—three uniquely human attributes—were present in some extinct pre-humans, would we then continue to look for newer, narrower definitions of what it means to be human?
just last year, we learnt that nearly 4% of our genes are of Neanderthal origin, suggesting much closer human contact with this extinct human cousin that lost the evolutionary race, than previously supposed. Are Neanderthals, then, more human or are we, Homo sapiens, less human? It would be much easier to just knock A. sediba off our evolutionary tree as an inconvenient truth.
Can fossils answer the mystery of our origins? Tell us at firstname.lastname@example.org